Question

Atomic #

Mass #
#p
#e
#n
charge
Symbol
1) 17
19
0
2)
180
71
109
3)
40
38
46
4) 92
238
86
206
5)
Pb4
82
6)
34
45
-2
7)
113
48
49
8) 21
42
0
31
9)
p.
15
10)
83
80
126

Answer 1

In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).